I looked at your blog and I see you have some banners in your sidebar, so putting in new ones at the bottom shouldn't be hard. You add them to the template the same way.

Go past the "</ul>" tag that ends your side menu in the "index.php" and enter the code for the new banners you've chosen. Even if html makes your head spin, since you've already put in ads before, you should be able to use that as a reference for adding the new ones.